yes, takethatlady, let's say that it means whatever the wearer wants it to mean. It's a great idea because, unlike what CagedBird says, this is not about Islam, strictly speaking.
If, as a non-Muslim woman, I were to start walking around fully covered up, by whatever mean I chose (remember Michael Jackson...), it would not be acceptable.
Because no one would know who I am
Because no one would know that when talking to them I am actually pulling faces or smirking or smiling
Because, if there were two of us who decided to do the same and walk around together, no one would know who is who
Because in short it would stop me from interacting with the rest of society. It would isolate me from 'the other'.
If you want to cover your head/hair as a sign of modesty (as other religions do), go ahead.
But I object to a full niqab which only allows one to see the eyes.
Everything else it represents or means is a different matter.